At present there are methods and devices for assisting the piloting of an aircraft during a phase of landing on a runway. U.S. Pat. No. 8,275,501 B1 describes such a method or such a device. Such a method or device is a unit called a runway overrun prevention system (or unit) or ROPS (standing for “Runway Overrun Prevention System” in English.
In general, these devices are intended for estimating the stopping point of the aircraft on the runway based on the capability of the aircraft to stop in nominal conditions. The adjective “nominal” qualifies the fact that there are no cases of failure that could degrade the deceleration capability of the aircraft.
If, at any point during the landing phase, the method or the device predicts that the aircraft will not be capable of stopping on the runway, at least one warning is triggered. Such a warning allows the crew to carry out a go-around maneuver if it is still possible to do this. If is it no longer possible to carry out a go-around and if the aircraft is on the ground, these warnings can also incite the crew to use any available means of deceleration, such as a maximum braking and a maximum thrust reversal, in order to stop the aircraft on the remaining length of the runway.
Thus, a unit of the ROPS type will emit a warning in the case of detection of a risk of runway overrun, in order to incite the crew to use any means of deceleration or to automatically initiate a means of deceleration. For example, a maximum braking can be triggered by the crew or triggered automatically and a maximum thrust reversal can be triggered by the crew. Such a warning represents a final safety net so that the pilot can initiate an emergency action.
When the aircraft is in flight or on the ground, the ROPS unit computes in real time a stopping distance which corresponds to a distance an aircraft travels in order to stop on a runway. This stopping distance is continually compared with the length of the runway remaining in front of the aircraft. Thus, if the computed stopping distance is greater than the length of the runway, dedicated warnings are emitted. These warnings can correspond to messages displayed on the main flight screen (PFD, standing for “Primary Flight Display” in English) and an audible warning from loud speakers. These dedicated warnings thus separate the world into a white region in which no warning is emitted and a black region in which the dedicated warnings are emitted.
The ROPS unit comprises two sub-functions: a Runway Overrun Warning function (ROW standing for “Runway Overrun Warning” in English) and a Runway Overrun Prevention function (ROP standing for “Runway Overrun Prevention” in English). The ROW function allows the generation of warnings inciting the crew to go around whilst the ROP function allows the generation of warnings inciting the crew to activate deceleration devices. The ROW function is active starting from a predetermined height, for example 500 feet (152 m), and remains active until a decision point. After this decision point, the ROP function is active. The ROP function remains active until the aircraft AC attains a run speed.
The decision point can correspond to the detection of a solid ground condition, that is to say a condition corresponding to the fact that the automatic brakes (“autobrakes” in English”) are activated and that the ground spoilers (“ground spoilers” being the English term) are deployed. This decision point can therefore be represented by the following logic:
the decision point is confirmed if at least one of the following conditions is met:                the main landing gears (MLG standing for “Main Landing Gears” in English) and the nose landing gear or gears (NLG standing for “Nose Landing Gears” in English) have been compressed for 1 s;        the full deployment of the ground spoilers has been requested.        
One of these two conditions can be met if the automatic braking is activated.
For certain aircraft, there are no available means for the crew to be able to anticipate a warning generated by the ROPS unit since no other indication apart from that of the warning is provided to the crew.
For other aircraft, indications are provided to the crew by the intermediary of an airport navigation screen (“airport navigation display” in English) but at least one action by the crew is necessary in order to access these indications. Moreover, the display of these indications can mask the navigation and monitoring information which must be monitored during the landing phase.
Consequently, the continuous display of these indications is not possible during the landing phase.